I'm sorry to hear that. First, I should mention that I'm not able to provide you advice on what you should do next. However, I am able to provide some information that might be relevant and helpful. Regarding the poaching of employees - I'm not sure what can be done on that front. If there is some provision in the contract between a company and their customer or in the contracts of these workers (with the company) that provides the workers cannot be poached by the customer, potentially, the company might be able to block their employees from jumping to their customer during the job. Granted, if a customer hired away workers from a company then broke the contract, there could be some relief due to a breach of the contract or based on the customer's interference with the company's ability to perform their contract. Regardless - it can be hard to restrict the mobility of employees, even where some contractual provision attempts to temper it.
Looking to the nonpayment, when construction work has been performed and unpaid, there are a number of potential recovery options - let's break a few of them down. For one, threatening to file a mechanics lien can go a long way toward compelling payment. By sending a document like a Notice of Intent to Lien, a claimant can show that they mean business about getting paid, and the they're willing to do what it takes to be paid what they've earned. You can learn more about that here: What is a Notice of Intent to Lien? The mere threat of a mechanics lien can be really effective, but sometimes, filing a mechanics lien might be necessary to get a claimant paid what they've earned. When a mechanics lien is filed, it puts the project property in jeopardy, and it grabs the attention of everyone on the job - putting pressure on the claimant's customer to own up to their side of the bargain. You can learn more about the mechanics lien option with these resources: (1) How Do Mechanics Liens Work?; (2) North Carolina Mechanics Lien & Notice FAQs; and (3) How to File a North Carolina Mechanics Lien. Of course, there are other options available outside of the mechanics lien process - potentially including recovery under prompt payment laws, breach of contract, and/or unjust enrichment, to name a few. Of course, recovery under any of these theories may require legal action. However, much like with a lien, the threat of legal action will often compel payment - so sending a demand letter specifying what legal action will be taken could work to force payment. When a demand letter is sent via an attorney, it will typically carry a little more "umph". Finally, before deciding whether legal action (i.e. filing a lawsuit) is a desirable option, it's a good idea to consult a local construction attorney. They'll be able to review your circumstances and any documentation, then provide advice n how best to proceed in your specific situation.